Lumens and foot-candles essentially measure the same thing--the amount of light arriving at an object or area you want to illuminate. The only catch is that lumens are usually interpreted to measure the amount of light arriving in one square meter--the metric system--while foot-candles measure how much light arrives at a given object one foot away from the light source. The foot-candles measurement is equal to lumens per square foot, so to convert from foot-candles to lumens, you must simply make the conversion from square feet to square meters.
- Pen and paper
Calculate the appropriate foot-candles measurement for a given light, either through research--by placing a light meter one foot away from that light in a completely dark room and reading the measurement--or by checking the product literature.
Divide the foot-candles measurement by .0929.
Note down the resulting number as “lumens/square meter.”